PHOTOSENSITIVE LITHOGRAPHIC PRINTING PLATE AND PLATE MAKING METHOD

摘要

PURPOSE:To obtain a photosensitive lithographic plate without the printing durability being decreased, excellent in sensitivity and developability and capable of erasing the film edge part of an original by providing a positive photosensitive composition layer on a sandblasted and anodically oxidized substrate. CONSTITUTION:A positive photosensitive composition layer contg. an O-quinone diazide compd. alkali-soluble resin and clathrate compd. is provided on a sandblasted and anodically oxidized substrate. The O-quinone diazide compd. is a polycondensed resin having an O-quinone diazide group and >=3000mol.wt., and the clathrate compd. is preferably selected from cyclic D-glucans and cyclophanes. A hydrophilic layer is preferably provided on the substrate which has been sandblasted, anodically oxidized and sealed. This positive photosensitive lithographic printing plate is picture-exposed with a developer contg. alkali metal silicate. As a result, a deposit is not formed in the developer bath.